1. Field:
The invention relates to flexible pipe retrieving vehicles and to processes for retrieving flexible plastic pipe from above-ground installations, especially in oil and gas field use.
2. Prior Art:
Flexible pipe in an oil or gas field installation is presently recovered in several ways. One method is to use a truck having a large reel mounted thereon which has one end of the pipe attached to the reel. The truck is driven towards the pipe while a man on the truck guides the pipe onto the reel so that it will lay properly on the reel. This, of course, has certain disadvantages inasmuch as there is a person on the truck while it is being driven over frequently rough terrain. The individual could lose his balance and be injured. Also, this method requires both a driver for the truck and a person on the truck to guide the pipe. Also, as the pipe is being retrieved it is difficult work in handling the pipe so that the operation is limited to the strength and stamina of the individual on the truck.
Another technique used for recovering flexible pipe is that illustrated in U.S. Pat. No. 3,995,355 to Sneed et al. The Sneed technique is one wherein the pipe is recovered by cutting the pipe into short segments. Each segment is attached to the reel. The reel is rotated to drag the pipe onto the reel while the truck is stationary. The truck then proceeds to the next segment whereby the segments are fused together and the pipe is then reeled onto the reel with the truck being stationary. This method has disadvantages inasmuch as someone must first go over the string of pipe, which frequently may be one to several miles in length and cut the pipe into short segments. The pipe is then drug over the ground and is thus abraded and worn.
Other patents which have some pertinence to the instant invention are the patents to Walker, U.S. Pat. No. 3,531,059, which describes a vehicle for recovering fire hose. Walker discloses a pickup tube over the front of the truck wherein the tube terminates there at a level below the hood level.
U.S. Pat. No. 3,070,324 to Bryman relates to a portable wire reeling device. The device comprises a jeep or other small vehicle for reeling and unreeling transmission cable, that is, communication cable. A stall standard is placed in front of the vehicle with an eyelet for the cable to pass through. The cable may be recovered by driving the vehicle into the line to recover it. Recovery of cable is an easier task than recovering of flexible pipe which is generally two or more inches in diameter. Also, cable is more durable and there is less damage caused by dragging the cable over rough terrain and less harm to the cable if the vehicle runs over it.
Flexible pipe can be permanently damaged during recovery in the event the vehicle runs over the pipe in rough terrain. Oftentimes the damage would not be discovered until after the pipe had been used a second time and a number of leaks discovered in the pipe string. Thus, a recovery method for flexible pipe must treat the pipe as gently as possible considering the difficulty of the terrain and the difficulty of discovering and repairing leaks. This is particularly true since flexible pipe often carries natural gas to the drilling sight for use in driving motors. Not only could a substantial amount of gas be lost but a potential fire and/or explosion hazard could exist.